Cycloalkylated beta-glucoside

ABSTRACT

There are disclosed a compound represented by the following general formula I wherein R represents a cyclic hydrocarbon group, and n represents 0 (zero) or an integer not less than 1, as well as β-glucosidase inhibitor, aromatic substance formation inhibitor, plant life lengthening agent, each of which contains at least one of compound represented by the aforementioned general formula I as an active ingredient, and plant or a part thereof in which formation of aromatic substance is inhibited by the aforementioned aromatic substance formation inhibitor. The present invention provides a novel compound that has β-glucosidase inhibition activity and can easily be produced in an industrial process, as well as a β-glucosidase inhibitor and aromatic substance formation inhibitor each containing such a novel compound as an active ingredient, and plant or part thereof in which the formation of aromatic substances is inhibited by the aforementioned aromatic substance formation inhibitor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cycloalkyl β-glucoside, aβ-glucosidase inhibitor, an aromatic substance formation inhibitor thatinhibits the formation of plant aromatic substance, and a plant or apart thereof in which the formation of aromatic substances is inhibitedby the aforementioned aromatic substance formation inhibitor, as well asa plant life lengthening agent.

2. Description of Related Art

As inhibitors for enzymes which hydorolyzed glycosidic linkages such asglucosidase, various substances including saccharides and proteinsderived from plants and microorganisms, synthetic oligosaccharidederivatives and the like have hitherto been reported. Among those, asfor inhibitors of β-glucosidase, many substances derived frommicroorganisms or plants and obtained by organic synthesis have beendescribed. Examples of such substances include, as for those derivedfrom microorganisms or plants, nojirimycin (T. Niwa et. al., Agric.Biol. Chem. 34. 966 (1970)), 1-deoxynojirimycin (G. Legler et. al.,Carbohydr. Res., 128, 61 (1984)), castanospermine (U. Fuhrann et. al.,Biochem. Biophys. Acta., 825, 95 (1985)),2,5-dihydroxymethyl-3,4-dihydroxypyrrolidine (A. Welter et. al.,Phytochem. 15, 747 (1976), validamine (S. Ogawa et. al., J. Chem. Soc.Chem. Commun., 1843 (1987) and the like, and as for those obtained byorganic synthesis, aminocyclopentane polyol (R. A. Farr et. al.,Tetrahedron Lett., 31, 7109 (1990), cyclic amidine (G. Papandreou et.al., J. Am. Chem. Soc. 115, 11682 (1993), cyclic guanidine (J. Lehmannet. al. Leiebigs Ann. Chem., 805 (1994), and the like. These inhibitorsare analogues of the substrates for glucosidases containing a nitrogenatom without exception.

These inhibitors, are useful physiological active substances which canbe used for various biochemical researches as an enzyme reactionanalysis reagent, an affinity carrier, a agent for analysis of functionand recognition mechanism of glycoprotein and the like, and it has alsobeen attempted to utilize them as medical or agricultural chemicals inthese days. These inhibitors which are expected to be applicable invarious fields, as mentioned above, have been conventionally beenproduced by extraction from microorganisms or plants, or by organicsynthesis.

However, in the case of those substances derived from microorganisms, itis quite difficult to purify such inhibitors from microbial culturebroth. As for those ones derived from plants, their present amount isvery little in the first place, and hence it is difficult to extract andpurify them from plants. Thus, the both methods involve many problems asa method for industrial production. For example, they suffer fromlimitations concerning with cost, yield and the like. Further, most ofreported conventional β-glucosidase inhibitors are their substrateanalogues containing a nitrogen and therefore it is not easy to producethem through enzymatic synthesis or organic synthesis. That is, in thecase of organic synthesis, only for introducing a nitrogen atom into asaccharide structure, several steps of organic synthesis reaction arerequired to perform, and hence it is disadvantageous as an industrialprocess. For the aforementioned reasons, it has hitherto been difficultto industrially produce glucosidase inhibitors which is utilizable forbiochemical applications. Therefore, there has been desired an inhibitorhaving a relatively simple structure of which industrial production ispossible.

By the way, a method for changing plant fragrance has been known, whichcomprises allowing a plant to absorb an aromatic substance, β-glucoside(Japanese Patent Unexamined Publication [KOKAI] No. 6-336401). Thismethod consists, of adding aroma to a plant. Therefore, it wasinsufficient for improving aroma of plant with an unpleasant smell.Further, there has also been known changing plant fragrance by adding adihydric alcohol such as propylene glycol as plant fragrance deodorizingagent (Japanese Patent Unexamined Publication [KOKAI] No. 10-33647).Although this patent document describes that unpleasant smell of plantcould be deodorized by adding a dihydric alcohol, its effectiveness wasnot satisfactory one. Further, while it is of course required to reducefragrance of plants generally considered to be unpleasant, for example,that of gypsophila, lily, chrysanthemum etc., it may be also desirableas the case may be to reduce fragrance of plants considered pleasant,for example, that of rose, jasmine, lavender and the like. Therefore, ithas been desired to develop an aromatic substance formation inhibitorthat acts on any kind of aroma.

Currently, as plant aromatic substances, there are known, for example,monoterpene alcohols such as geraniol and citronel, aromatic alcoholssuch as phenethyl alcohol and benzyl alcohol and the like. Thesealcohols are contained in various flowers, teas, fruits, wines and thelike, and it has become clear that they also exist as glycosides inaddition to their free forms. Further, there have also been reportedthat the aromatic substance precursors of the aromatic substances suchas geraniol and phenethyl alcohol, which are major aromatic substancesof rose and the like, are β-glucosides, and biosynthesized in leaves andpetals, respectively, and that β-glucosidases play an important role inthe production process of aromatic substances (I. E. Ackermann et. al.,J. Plant Physiol., 134, 567-572 (1989); K. Sakata, Oyo Tositsu Kagaku[Applied Saccharide Science], Vol.45, No.2, 123-129 (1998)).

That is, plant fragrance is formed by a mechanism that the aromaticsubstance precursor, β-glucoside, is hydrolyzed by β-glucosidase toliberate an aromatic substance. If the function of β-glucosidase in thismechanism can be inhibited, the aromatic substance precursor,β-glucoside, would not be hydrolyaed, and hence an aromatic substancewill not be formed or its formation will be reduced. That is, it can beconsidered that, if β-glucosidase can be inhibited, the aromaticsubstance to be liberated is reduced and smell can be reduced.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a novelcompound that has β-glucosidase inhibition activity and can easily beproduced in an industrial process. Furthermore, another object of thepresent invention is to provide an aromatic substance formationinhibitor containing such a novel compound as an active ingredient, andplant or part thereof in which the formation of aromatic substances isinhibited by the aforementioned aromatic substance formation inhibitor.

As a result of the present inventors' researches, it was found thatcycloalkyl β-glucosides which can be easily produced by organicsynthesis or enzymatic synthesis had the β-glucosidase inhibitionactivity. Because these β-glucosides do not contain a nitrogen atom,their synthesis does not require any complicated synthetic process forintroducing a nitrogen atom, and hence they can be produced by arelatively simple synthetic process, which means that their industrialproduction is possible. Furthermore, the present inventors studiedvarious candidate aromatic substance formation inhibitors for plantsfrom the viewpoint of searching substances capable of inhibitingβ-glucosidase to prevent the hydrolysis of β-glucoside, therebyinhibiting the formation of aromatic substances, to find aromaticsubstance formation inhibitors for plants that have suitable activityfor alleviating unpleasant smell and strong aroma of plants. As aresult, it was unexpectedly found that the aforementioned cycloalkylβ-glucosides had marked activity for inhibiting the formation of plantaromatic substances and consequently reducing the amount of aromaticsubstances released from plants, and further found that they did notproducing phytotoxicity against plants and also had life lengtheningeffect. Thus, they accomplished the present invention.

Cycloalkyl β-glucoside

The present invention relates to compounds represented by the followinggeneral formula (I).

In the formula, R represents a cyclic hydrocarbon group, and nrepresents 0 (zero) or an integer not less than 1.

The present invention also relates to a β-glucosidase inhibitor whichcontains at least one of compound represented by the aforementionedgeneral formula I as an active ingredient; an aromatic substanceformation inhibitor which contains at least one of compound representedby the aforementioned general formula I as an active ingredient; a plantor a part thereof in which formation of aromatic substance is inhibitedby the aforementioned aromatic substance formation inhibitor; and aplant life lengthening agent which contains at least one of compoundrepresented by the aforementioned general formula I as an activeingredient.

PREFERRED EMBODIMENTS OF THE INVENTION

Cycloalkyl β-glucoside

In the general formula (I), n is 0 (zero) or an integer not less than 1,and does not have any particular upper limit. However, considering easeof production, for example, if a raw material is commercially availableor not, n is preferably 3 or less. Of course, it is not intended toexclude those compounds where n is 4 or more.

In the general formula (I), R represents a cyclic hydrocarbon group, andspecific examples thereof include a cyclopropyl group, a cyclobutylgroup, a cyclopentyl group, a cyclohexyl group and the like.Specifically, it can be selected from the group consisting of acyclopropylmethyl group, a cyclopentylmethyl group, a 2-cyclopentylethylgroup, a 3-cyclopentylpropyl group, a cyclobutyl group, a cyclopentylgroup and the like. Examples of the compound of the present inventionrepresented by the aforementioned general formula (I) are, specifically,cyclopropylmethyl β-glucoside, cyclobutyl β-glucoside, cyclobutylmethylβ-glucoside, cyclopentyl β-glucoside, cyclopentylmethyl β-glucoside,2-cyclopentylethyl β-glucoside, 3-cyclopentyl-1-propyl β-glucoside andthe like.

The cycloalkyl β-glucoside of the present invention can be synthesizedeither by an organic synthetic process or enzymatic synthesis process.For the organic synthesis process, a method comprising a known reactionof glucose and alcohol in the presence of an acid catalyst can be used,and the compounds can be readily produced by one step through such amethod (see Japanese Patent Unexamined Publication [KOKAI] No.48-32846). As the aforementioned catalyst, hydrochloric acid, sulfuricacid, strongly acidic cation exchange resin and the like can be used.The cycloalkyl β-glucoside can be produced by adding the catalyst to amixture of saccharide and alcohol, and stirring the mixture at areaction temperature of 0-100° C. In addition to the above method, amethod utilizing the known Koenigs-Knorr reaction to exclusivelysynthesize a β-linked compound (Yu Kagaku [oil Science], Vol. 43, No. 1,31-38, (1994)) can also be used for the present invention.

As for the enzymatic synthesis process, the compound can readily besynthesized by utilizing the known transglucosylation reaction byβ-glucosidase (see Japanese Patent Unexamined Publication No. 63-25859).Specifically, the β-glucoside can be produced by utilizing a cellulosicsaccharide such as cellobiose, holocellulose, and xylan as a donorsubstrate, and an alcohol as an acceptor substrate, and allowingβ-glucosidase to act on them.

As the cyclic alcohol used as a raw material in the aforementionedorganic synthesis or the enzymatic synthesis, cyclopropanol,cyclobutanol, cyclobutylmethanol, cyclopentanol, cyclopentylmethanol,2-cyclopropylethanol, 3-cyclopropyl-1-propanol and the like can bementioned.

The obtained product containing β-glucoside can be further purified ifrequired. As the method which can be used for the purification, forexample, gel filtration chromatography, strongly acidic cation exchangeresin chromatography, adsorption chromatography and the like can bementioned. Specifically, the purification can be performed as follows. Areaction mixture of organic synthesis or enzymatic reaction is loaded ona column filled with a synthetic adsorption resin so that the cycloalkylβ-glucoside should be adsorbed on the resin, and the column is washedwith water for removing un-adsorped materials. Then, the adsorbedcycloalkyl β-glucoside is eluted with 30 to 100% methanol to obtainconcentrated cycloalkyl β-glucoside. The obtained concentrate canfurther be purified by gel filtration chromatography.

βGlucosidase Inhibitor

The β-glucosidase inhibitor of the present invention comprises as anactive ingredient at least one of the β-glucoside represented by theaforementioned general formula (I). The β-glucoside represented by theaforementioned general formula (I), and the group R and the cyclichydrocarbon group in the general formula (I) are similar to thoseexplained above for the cycloalkyl β-glucoside of the present invention.

While the β-glucosidase inhibitor of the present invention can be usedfor both of β-glucosidases derived from plant and microorganism, it canpreferably be used for β-glucosidase derived from plant.

Aromatic Substance Formation Inhibitor and Plant or Part thereof inwhich Formation of Aromatic Substance is Inhibited

The aromatic substance formation inhibitor of the present inventioncomprises as an active ingredient at least one of the β-glucosiderepresented by the aforementioned general formula (I). The β-glucosiderepresented by the aforementioned general formula (I), and the group Rand the cyclic hydrocarbon group in the general formula (I) are similarto those explained above for the cycloalkyl β-glucoside of the presentinvention.

The aromatic substance formation inhibitor of the present invention canbe used for the inhibition of plant aromatic substance formation. As theplant of the present invention, therophytes, perennial herbaceousplants, and flowering trees such as gypsophila, lily, chrysanthemum,rose, jasmine, lavender, tulip, carnation, orchid, and sweet pea can bementioned. However, it is not limited to these categories. The aromaticsubstance formation inhibitor of the present invention inhibits theformation of aromatic substance by inhibiting the aromatic substanceformation in plant bodies. Therefore, the plant of which formation ofthe aromatic substance should be inhibited may be one in a state thatthe aromatic substance can be formed. For example, they may be cutflowers or those cultured in open, house, flowerpot and the like.

Since the aromatic substance formation inhibitor of the presentinvention exhibits high solubility in water and storage stability as anaqueous solution, it can be used as an aqueous solution, for example.Since the aromatic substance formation inhibitor of the presentinvention inhibits the activity of β-glucosidase in a plant body, theinhibitor must be introduced into the plant body in order to obtain thearomatic substance formation inhibition effect in the plant body by theinhibitor. To this end, for example, the following methods can be used.

When an aqueous solution is used for inhibiting the formation of thearomatic substance of plants, for example, in the case of cut flowers,cut ends of the cut flowers can be immersed in the aqueous solution ofthe aromatic substance formation inhibitor of the present invention, andthereby the aromatic substance formation inhibitor of the presentinvention can be absorbed through vessels of the cut flowers. Thisoperation can be carried out easily, since special treatment is notrequired. Furthermore, such an aqueous solution as mentioned above cansimilarly be used in many scenes, for example, when flowers aretemporarily immersed in water after the harvest by producers, when cutflowers are sold in shops such as flower shops in containers such asbuckets, when cut flowers are arranged in vases at home, hospital,exhibition, etc. and the like. Further, such an aqueous solution canalso be used for affusion or direct spraying on leaf surfaces so thatthe inhibitor should be absorbed in a plant, thereby inhibiting theformation of the aromatic substance of the plant. This method can beused for, for example, cut flowers and plants grown on open, in houses,flowerpots and the like. Specifically, an aqueous solution of thearomatic substance formation inhibitor of the present invention in asuitable amount can be affused into soil or sprinkled on leaf surfacesof plants.

Although concentration of the cycloalkyl β-glucoside used as an aromaticsubstance formation inhibitor of the present invention may varydepending on the kind of objective cut flowers or treatment time, whenused as an aqueous solution, it is generally preferable to use it withina concentration range of about 0.01 to 10% by weight volum, morepreferably about 0.1 to 3.0% by weight volum. The aromatic substanceformation inhibitor of the present invention can function so long as thecycloalkyl β-glucoside functions as an active ingredient. Therefore, thearomatic substance formation inhibitor and plant or a part thereof ofwhich formation of aromatic substance is to be inhibited may containimpurities, specifically, impurities introduced during the organicsynthesis or enzymatic synthesis, so long as the plant is not adverselyaffected.

Furthermore, the aromatic substance formation inhibitor of the presentinvention can be used with a known cut flower life lengthening agent,for example, those comprising saccharide and germicide, surface activeagent and the like, if required. Furthermore, the aromatic substanceformation inhibitor of the present invention can also containconventionally used nutrients such as nitrogen source, phosphoric acid,potassium source, sucrose, glucose, and vitamin C, trace amountnutrients such as iron, zinc, manganese, copper, and boron, B-nine,benzyladenine, brassinolide and the like.

The plant or part thereof in which the formation of the aromaticsubstance is inhibited by the aromatic substance formation inhibitor ofthe present invention means a plant or a part thereof in which theformation of the aromatic substance is inhibited by the aforementionedmethod utilizing the aromatic substance formation inhibitor of thepresent invention. The plant may be, for example, cut flowers or thosecultured in open, house, flowerpot and the like. The part of plant maybe, for example, a flower or a part containing flower, leaf or a partcontaining leaf, stalk or a part containing stalk and the like. As thekind of the aforementioned plant, for example, therophytes, perennialherbaceous plants, and flowering trees such as gypsophila, lily,chrysanthemum, rose, jasmine, lavender, tulip, carnation, orchid, andsweet pea can be mentioned. However, it is not limited to thesecategories.

Since formation of unpleasant aroma or aroma desired to be reduced isprevented in the plant or part thereof of the present invention, theemitted aromatic substance therefrom is reduced compared with thatoriginally emitted from the corresponding plant or part thereof.Therefore, the plant or part thereof can be used for their applicationswithout caring about their aroma. Specifically, when the aromaticsubstance formation of lily cut flowers is inhibited, they can be usedfor indoor decoration or the like without caring about their aroma,since their aroma said to be unpleasant is reduced.

Plant Life Lengthening Agent

The plant life lengthening agent of the present invention comprises asan active ingredient at least one of the β-glucoside represented by theaforementioned general formula (I). The β-glucoside represented by theaforementioned general formula (I), and the group R and the cyclichydrocarbon group in the general formula (I) are similar to thoseexplained above for the cycloalkyl β-glucoside of the present invention.

While the action mechanism of the plant life lengthening agent of thepresent invention is not clear, it gives to plant bodies lifelengthening effect without causing phytotoxicity. As the plant of thepresent invention, therophytes, perennial herbaceous plants, andflowering trees such as gypsophila, lily, chrysanthemum, rose, jasmine,lavender, tulip, carnation, orchid, and sweet pea can be mentioned.However, it is not limited to these categories. The plant lifelengthening agent of the present invention can be used for cut parts ofthe aforementioned plants, for example, cut flowers.

Since the plant life lengthening agent of the present invention isexcellent in solubility in water and storage stability as an aqueoussolution, it can be used as an aqueous solution, for example. When anaqueous solution is used for lengthening plant life, methods and amountssimilar to those used for the aqueous solution of the aromatic substanceformation inhibitor of the present invention for cut flowers can beused.

The present invention will be further explained with reference to thefollowing examples hereinafter.

EXAMPLE 1

Organic Synthesis of Cycloalkyl β-glucoside

Anhydrous glucose (1.0 g, 5.6 mol), strongly acidic cation exchangeresin Amberlyst 15E (ORGANO CORP., 1. 0 ml) and cyclopentanol (2.0 ml)were mixed and stirred sufficiently, and the obtained mixture wasincubated at 80 °C. The reaction mixture was sampled by collecting a 50μl portion into a microtube at constant intervals. Each collected samplewas added with 500 μl of 50% v/v methanol in purified water, andfiltered through a 0.45 μm membrane filter, and 10 μl of the filtratewas subjected to HPLC using a gel filtration column to trace thesaccharide composition. The aforementioned HPLC was performed by using acolumn Shodex Asahipak GS-220HQ (7.5 mm I.D.×500 mm), desalted water aseluate, and RI monitor as detector under the conditions of columntemperature of 60° C. and flow rate of 0. 6 ml /min. After the reactionwas performed for 24 hours, the obtained reaction mixture was cooled,and loaded on a column (2.5 cm I.D.×16 cm) filled with syntheticadsorptive resin HP-20 (Mitsubishi Chemical Co.), and washed with water.Then, the desired compound, cyclopentanol glycoside was eluted with 50%methanol, and concentrated. Further, the obtained concentrate wasadjusted to 5% w/v concentration and pH 6.0, and added with 50 U ofα-glucosidase from yeast at 40° C. to hydrolyze cycloalkyl α-glucosidecontained as an impurity. After 24 hours, the reaction mixture wasboiled for 5 minutes, removed unsloble materials by centrifugation, thenconcentrated the supernatant to 3 ml (40% w/v, 1.2 g as solid matter),and purified by gel filtration utilizing a column (5 cm, I.D.×95 cm)filled with Toyopearl HW-40S (Tosoh) and RI monitor as detector underthe conditions of column temperature of 65° C. and flow rate of 5 ml/minto obtain 500 mg of cyclopentyl β-glycoside having a purity of 99% ormore.

¹³C Nuclear magnetic resonance spectrum of the obtained cyclopentylβ-glycoside was determined in heavy water utilizing tetramethylsilane asa standard. As a result, the peaks at 23.4, 38.0, 61.4, 70.0, 73.4,75.2, 81.8, and 103.4 ppm were obtained. Further, ¹H nuclear magneticresonance spectrum was also determined. As a result, the anomeric protonwas observed at 4.48 ppm as a doublet peak, and the coupling constantwas 7.91 Hz. From these results, it could be confirmed that the obtainedglycoside was cyclopentyl β-glucoside.

Furthermore, the same reaction and HPLC analysis as mentioned above wererepeated by using cyclobutanol, cyclopentylmethanol,2-cyclopentylethanol, and 3-cyclopentyl-l-propanol instead ofcyclopentanol. As a result, the formation of β-glucoside could beconfirmed for each case.

EXAMPLE 2

Enzymatic Synthesis of Cycloalkyl β-glucoside

Cellobiose (10 g, final concentration; 25% w/w), 100 mM sodium acetatebuffer (pH 5.0, 2 ml), pure water (30.4 ml), and cyclopentylmethanol (5ml) were mixed sufficiently, added with 5 U of enzyme preparationcontaining β-glucosidase derived from Trichoderma viride (Cellulase,SIGMA), and left stand for reaction at 45° C. The reaction mixture wassampled by collecting a 50 μl portion into a microtube. Each collectedsample was boiled for 5 minutes, added with 500 μl of purified water,and filtered through a 0.45 μm membrane filter, and 10 μl of thefiltrate was subjected to the same HPLC as in Example 1 to trace thesaccharide composition. After the reaction by β-glucosidase for 48hours, the obtained reaction mixture was boiled for 10 minutes toinactivate the enzyme. The reaction mixture was loaded on a column (2.5cm I.D.×16 cm) filled with synthetic adsorptive resin HP-20 (MitsubishiChemical Co.), and washed with water, and cyclopentylmethanol glycosidewas eluted with 50% methanol, and concentrated. The reaction mixtureconcentrated to 3 ml (40% w/v, 1.2 g as solid matter) was purified bygel filtration utilizing a column (5 cm, I.D.×95 cm) filled withToyopearl HW-40S (Tosoh) and RI monitor as detector under the conditionsof column temperature of 65° C. and flow rate of 5 ml/min to obtain 500mg of cyclopentylmethanol glycoside having a purity of 99% or more.

¹³C Nuclear magnetic resonance spectrum of the obtainedcyclopentylmethanol glycoside was determined in heavy water utilizingtetramethylsilane as a standard. As a result, the peaks at 27.8, 31.8,31.9, 41.5, 63.5, 72.5, 76.0, 78.0, 78.7, 78.8, and 105.2 ppm wereobtained. Further, ¹H nuclear magnetic resonance spectrum was alsodetermined. As a result, the anomeric proton was observed at 4.45 ppm asa doublet peak, and the coupling constant was 7.92 Hz. From theseresults, it could be confirmed that the obtained cyclopentylmethanolglycoside was cyclopentylmethyl-β-glucoside.

Furthermore, the same reaction and HPLC analysis as mentioned above wererepeated by using cyclopropylmethanol, cyclobutanol, andcyclopentylethanol instead of cyclopentylmethanol. As a result, theformation of β-glucoside could be confirmed for each case.

EXAMPLE 3

β-Glucosidase Inhibition Test

β-Glucosidase inhibition test was performed as follows. 10 mMp-nitrophenyl-β-glucoside (100 μl, abbreviated as pNP-β-Glchereinafter), 1 M sodium acetate buffer (pH 5.0, 50 μl), pure water, and100 mM inhibitor (10 μl) were taken into a short test tube so that themixture should have a total volume of 800 μl, and preincubated at 40° C.for 5 minutes. After the incubation, the obtained mixture was added with50 μl of enzyme solution diluted to a suitable concentration, andallowed to react at 40° C. After 10 minutes, the enzyme was inactivatedby adding 500 μl of 1 M sodium carbonate to the obtained reactionmixture, and the absorbance at 405 nm was measured and used forcalculation of the amount of free p-nitrophenol. As the inhibitor,cyclopropylmethyl-β-glucoside (CPAM-β-Glc), cyclopentyl-β-glucoside(CPE-β-Glc), and cyclopentylmethyl-β-glucoside (CPEM-β-Glc) all preparedby the methods of Examples 1 and 2were used. As the β-glucosidase,chromatographically purified preparations derived from Aspergillusniger, Trichoderma viride, and Almond (all from SIGMA) were used.

TABLE 1 Effect of cycloalkyl glucoside (1 mM) on pNP-β- glucosidaseactivity Enzyme Inhibitor Activity ratio 1) A. niger No inhibitor 1.00CPMA-β-Glc 0.94 CPE-β-Glc 0.92 CPEM-β-Glc 0.99 2) T. viride No inhibitor1.00 CPAM-β-Glc 1.01 CPE-β-Glc 1.06 CPEM-β-Glc 1.05 3) Almond Noinhibitor 1.00 CPAM-β-Glc 0.86 CPE-β-Glc 0.90 CPEM-β-Glc 0.27

As shown in the above results, under the aforementioned experimentalcondition (inhibitor concentration of 1.25 mM), CPEM-β-Glc stronglyinhibited the β-glucosidase derived from almond, but showed relativelyweak inhibition for that derived from A. niger, and no inhibition forthat derived from T. viride. Therefore, the measurement was furtherperformed under the same conditions as those mentioned above with aconcentration of CPEM-β-Glc varying from 0 to 5 mM. As a result, the 50%inhibition concentration of CPEM-β-Glc for the β-glucosidase derivedfrom almond was found to be 0.17 mM, and 50% inhibition concentrationsfor β-glucosidases derived from A. niger and T. viride were found to be12.61 and 11.54 mM, respectively. Thus, it was demonstrated that,although CPEM-β-Glc showed difference in the effective concentration(50% inhibition concentration for β-glucosidase derived from almond wasabout 70 times higher than 50% inhibition concentrations forβ-glucosidases derived from A. niger and T. viride), it inhibited all ofthe β-glucosidases.

EXAMPLE 4

Inhibition Test for Rose Crude Enzyme

Only petals (about 70 g) were collected from about ten marketed roses(variety; Rosa gybrida CV. Wendy), added with acetone (500 ml) cooled to−20° C., and pulverized by a homogenizer while cooled with dry ice. Theobtained pulverized mixture was filtered through a Buchner funnel putwith a No. 2 filter paper sheet, and sufficiently washed with acetone at−20° C. The obtained filtrate was dried in a desiccator under reducedpressure (room temperature, 3 hours) to obtain 6 g of crude enzymepowder. This powder was added to 100 mM sodium phosphate buffer (pH 7.0,120 ml) and stirred at 4° C. for 3 hours, and the insoluble matter wasremoved by centrifugation. The filtrate was subjected to ultrafiltrationutilizing an ultrafiltration membrane PM-10 (Amicon) to finally afford15 ml of crude enzyme solution.

In the same manner as in Example 3, the inhibition activity of theCPEM-β-Glc obtained in Example 2 for the pNP-β-Glc activity of the abovecrude enzyme solution was measured. The measurement was performed byvarying the concentration of the added CPEM-β-Glc from 0 to 5 mM. As aresult, the inhibition activity was about 50% at 3 mM, about 70% at 4mM, and about 90% at 5 mM.

EXAMPLE 5

Aromatic Substance Formation Inhibition Effect in Cut Flowers

A 0.13% (w/v, 5 mM) aqueous solution of the CPEM-β-Glc obtained inExample 2 was prepared. The obtained aqueous solution (300 ml) wasintroduced into an Erlenmeyer flask, and lily, chrysanthemum, andgypsophila were put into it one for each. On the other hand, as control,the flowers were similarly put into water without the CPEM-β-Glc. After1, 2 and 4 days, organoleptic test was performed by ten expert panelistsas for the aroma emitted from these cut flowers. As a result, after oneday, all of the expert panelists judged that the aroma was distinctlyreduced when the CPEM-β-Glc was added as for all of lily, chrysanthemum,and gypsophila. No difference in freshness of the cut flowers wasobserved between the cases where the CPEM-β-Glc was added or not added.

EXAMPLE 6

Life Lengthening Effect for Cut Flowers

A 0.13% (w/v, 5 mM) aqueous solution of the CPEM-β-Glc obtained inExample 2 was prepared. The obtained aqueous solution (50 ml) wasintroduced into an Erlenmeyer flask, and a rose (variety; Rosa gybridaCV. Dukat) in a budding state was put into it. On the other hand, ascontrol, the flower was similarly put into water not added with theCPEM-β-Glc. The flowers were left at room temperature, and droop of theflowers was observed. The flower did not droop by the 7th day whenCPEM-β-Glc was added, whereas the flower drooped on the 5th day whenCPEM-β-Glc was not added.

Unlike β-glucosides containing a nitrogen atom, of which industrialproduction is difficult, the compounds of the present inventionrepresented by the general formula (I) have a relatively simplestructure, and therefore they can be produced by an organic synthesisprocess or enzymatic synthesis process suitable for the industrialproduction. Therefore, it has become possible to industrially produceand provide β-glucosides, of which industrial production has hithertobeen difficult. By utilizing the β-glucosidase inhibition activity ofthe compounds represented by the general formula (I) of the presentinvention, for example, it has become possible to provide plant aromaticsubstance formation inhibitors containing the foregoing compounds as anactive ingredient and capable of alleviating unpleasant fragrance orunnecessarily strong fragrance of cut flowers and the like, and plantbodies whose aromatic substance formation is inhibited by the aromaticsubstance formation inhibitors. Because the cycloalkyl β-glucosides ofthe present invention are a non-odorous substance, an inhibition effectfor the aromatic substance formation is not degraded by the odor of theβ-glucosides themselves. Further, because the aromatic substanceformation inhibitors of the present invention do not show phytotoxicityagainst plants, they can be used without caution. Furthermore, becausethe compounds of the present invention also have plant life lengtheningeffect, they can be readily used as a plant life lengthening agentwithout showing phytotoxicity.

What is claimed is:
 1. A compound represented by the following generalformula I:

wherein R represents a cyclic hydrocarbon group selected from the groupconsisting of a cyclopropylmethyl group, a cyclopentylmethyl group, a2-cyclopentylethyl group, a 3-cyclopentylpropyl group, cyclobutyl group,and a cyclopentyl group, and n represents 0 (zero) or an integer notless than
 1. 2. The compound of claim 1 wherein the n is not greaterthan
 3. 3. An aromatic substance formation inhibiting compositionconsisting essentially of at least one compound of claim 1 as an activeingredient.
 4. A plant life lengthening composition consistingessentially of at least one compound of claim 1 as an active ingredient.5. A compound according to claim 1, wherein said compound iscyclopropylmethyl β-glucoside, cyclobutyl β-glucoside, cyclobutylmethylβ-glucoside, cyclopentyl β-glucoside, cyclopentylmethyl β-glucoside,2-cyclopentylethyl β-glucoside, or 3-cyclopentyl-1-propyl β-glucoside.